Aziz N, Nishanian P, Mitsuyasu R, Detels R, Fahey J L
CIRID at University of California, Los Angeles, Department of Microbiology and Immunology, Los Angeles, California 90095, USA.
Clin Diagn Lab Immunol. 1999 Jan;6(1):89-95. doi: 10.1128/CDLI.6.1.89-95.1999.
Cytokines and soluble immune activation markers that reflect cytokine activities in vivo are increasingly being measured in plasma, serum, and other body fluids. They provide useful diagnostic and prognostic information as well as insight into disease pathogenesis. Assays of neopterin, beta2-microglobulin, soluble interleukin-2 receptor, and soluble tumor necrosis factor receptor type II as well as of the cytokines tumor necrosis factor alpha and gamma interferon (IFN-gamma) were evaluated by using serum and plasma samples of human immunodeficiency virus (HIV)-positive and HIV-negative subjects. Many factors were found to influence the outcomes of these assays. Substantial differences in apparent levels of analytes were frequently found when enzyme-linked immunosorbent assay (ELISA) kits from different manufacturers were used. In some cases, differences were found in the standards provided by separate manufacturers. Furthermore, the analytic results from different lots of ELISA kits supplied by single manufacturers differed by as much as 50%. The need for uniformity in the standards for quantitative assays was clearly illustrated. International reference standards are available for cytokines but not for soluble cytokine receptors or soluble activation markers. Marker levels in serum or in plasma were similar except those for IFN-gamma. Most of the analytes were stable under several storage conditions. Thus, batch testing of frozen stored samples is feasible. The findings indicate that for longitudinal studies, the levels of cytokines and immune activation markers in plasma or serum should be measured by using preverified reagents from one manufacturer. The quality of laboratory performance can have an impact on clinical relevance. Proficiency testing and external quality assurance programs can help to develop the needed consensus.
反映体内细胞因子活性的细胞因子和可溶性免疫激活标志物越来越多地在血浆、血清及其他体液中进行检测。它们能提供有用的诊断和预后信息，还能深入了解疾病的发病机制。通过使用人类免疫缺陷病毒（HIV）阳性和HIV阴性受试者的血清和血浆样本，对新蝶呤、β2-微球蛋白、可溶性白细胞介素-2受体、可溶性肿瘤坏死因子受体II型以及细胞因子肿瘤坏死因子α和γ干扰素（IFN-γ）的检测方法进行了评估。发现许多因素会影响这些检测的结果。使用不同制造商的酶联免疫吸附测定（ELISA）试剂盒时，常常会发现分析物的表观水平存在显著差异。在某些情况下，不同制造商提供的标准品也存在差异。此外，同一制造商提供的不同批次ELISA试剂盒的分析结果差异高达50%。这清楚地表明了定量检测标准统一的必要性。细胞因子有国际参考标准品，但可溶性细胞因子受体或可溶性激活标志物没有。血清或血浆中的标志物水平除IFN-γ外相似。大多数分析物在几种储存条件下都很稳定。因此，对冷冻保存样本进行批量检测是可行的。研究结果表明，对于纵向研究，应使用来自同一制造商的经过预先验证的试剂来检测血浆或血清中的细胞因子和免疫激活标志物水平。实验室检测性能的质量会对临床相关性产生影响。能力验证和外部质量保证计划有助于达成所需的共识。
